om049554r_si_003.cif (17.98 kB)

Addition of Ynamines to the Tungsten η1-Vinylidene Complexes (η5-C5H5)(NO)(CO)WCC(H)R

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posted on 11.10.2004, 00:00 by Junes Ipaktschi, Javad Mohseni-Ala, Ansgar Dülmer, Stefan Steffens, Christian Wittenburg, Jürgen Heck
With the aim of synthesis of chiral-at-metal complexes with NLO properties, the reaction of ynamines 2a,b with the η1-vinylidene complexes (η1-C5H5)(CO)(NO)WC(H)R (R = C6H5 (1), C(CH3)3 (6), H (8)) was investigated. It has been shown that the substituent R on the η1-vinylidene complex determines the outcome of the reaction. Whereas the reaction of 2a,b with complex 1 gave rise to the expected cyclobutenylidene complexes 4a,b and 5a,b, the reaction of ynamines with complexes 6 yielded the aminocarbene complexes 7a,b and the reaction of η1-vinylidene complexes 8 gave rise to a mixture of compounds 9 and 10. The mechanism of formation of these complexes was investigated. Single-crystal X-ray diffraction data of 4a, 7a, and 9 are reported. Complex 4a is composed of a strong electron-donating and -accepting group conjugated via double bonds of a cyclobutenylidene unit. Hence, the first hyperpolarizability β was determined by hyper-Rayleigh scattering measurements with a stimulating laser beam at λ = 1500 nm. A first hyperpolarizability of β = 105 × 10-30 esu was determined.